Glen Courtright, CEO and founder of EnviroFlight, monitored the local company’s new product, a natural fertilizer for vegetable gardens, flowers and lawns, as it passed through a sifter. The fertilizer is a byproduct of EnviroFlight’s proprietary process of producing insect-based fish food. (Photo by Megan Bachman)

Getting from waste to want not

The busy bugs of EnviroFlight are churning out a new product this year — a natural fertilizer that some say is making area tomato plants grow like weeds.

The black soldier fly larvae at the MillWorks-based company will eventually become fish food, but before they do, their excretions are separated out and sold as a nutrient-rich plant food. Officially, the new fertilizer — Yellow Springs Select All-Natural Plant Food — is a byproduct of the EnviroFlight process. To the local start-up that feeds insects spent grains discarded by ethanol plants and breweries, it’s yet another way of turning waste into something useful.

“We like to call them co-products, not waste,” EnviroFlight CEO Glen Courtright said this week. “Waste has a negative connotation. The key to our business is nutrient recovery.”

Courtright, an engineer who previously worked in the biofuel industry, founded EnviroFlight in Yellow Springs in 2009.

Courtright boasts that Yellow Springs Select is free of chemicals and animal byproducts and that the ingredients to make it are all sourced within 50 miles. Even better, it actually works. Compared with commercial chemical fertilizers, which provide a quick boost of growth and can “burn” or even kill plants if over-applied, the nitrogen in Yellow Springs Plant Food is released into the soil more slowly, allowing for long-lasting plant growth that doesn’t cause burning, Courtright said.

Yellow Springs Plant Food is available by the 20-pound bag at the local Saturday morning Farmer’s Market and at Downing’s Do it Best Hardware, along with other area garden stores. EnviroFlight is also selling Yellow Springs Plant Food by the truckload to commercial fertilizer ­companies.

According to Courtright, when Yellow Springs Plant Food is mixed into the soil after plants are established, it helps the plants grow well by providing them with vital nutrients, beneficial bacteria and fungi. The fertilizer also helps to retain moisture in the soil and, when applied to the soil surface, can keep weeds at bay, he said.

“It has natural pre-emergent characteristics,” Court­right explained. “It’s great on lawns. You apply it to suppress weeds.”

Yellow Springs Plant Food has a nitrogen-phosphorus-potassium (N–P–K) ratio of 5–3–2 and is well suited for vegetable gardens, shrubs, lawns and as a compost catalyst, according to EnviroFlight’s website.

Most commercial inorganic fertilizer is made using a fossil fuel, natural gas, while organic fertilizers often contain animal manure, which can harbor pathogens. By contrast, Yellow Springs Plant Food contains no animal wastes or synthetic materials. First the black soldier fly larvae are bred onsite and bulked up with spent distillers grains from ethanol plants and brewers grains from the nearby Yellow Springs Brewery. Then the larvae are separated out to be processed into feed. What’s left, the frass, which includes the larvae’s excreta along with their shedded skins, are finely ground into the fertilizer. The resulting material is fibrous, so it helps keep moisture in the soil, and it is rich with the insects’ digestive juices, which contain beneficial enzymes that boost plant productivity, Courtright said.

Courtright built three experimental garden beds at MillWorks to test out his company’s latest product. In one he used commercial fertilizer, in another no fertilizer at all and in a third he applied Yellow Springs Plant Food. Radishes, kale, marigolds and especially the tomato plants grew best using Yellow Springs Plant Food, Courtright found.

“Good, better, best — nothing, corporate, local,” Courtright said, pointing first to the bed without any fertilizer applied, then to the one where commercial fertilizer was used and finally to the bed with Yellow Springs Plant Food.

Phil Hayden of Oakwood is one happy customer of Yellow Springs Plant Food. Hayden, who is also an EnviroFlight investor, reports that his tomato plants are growing like weeds on a patch of ground that last year, using commercial fertilizer, yielded poor results. Another enthusiast, longtime gardener Kobi Cornett of Dayton, said Yellow Springs Plant Food helped her garden vegetables and flowers perform better than with conventional fertilizer.

“With Miracle Grow, sometime you get all that beautiful foliage and nothing blooms,” she said. “I used it in May and with all the rain we’ve had, a week later my squash, zucchini and cucumbers exploded…I’ve never been this amazing of a gardener.”

EnviroFlight, now it its fourth year, supplies its insect-based feeds to zoos across the country and nationwide pet food distributors and to regional freshwater prawn farmers. The company is testing out feed formulations for yellow perch, rainbow trout and tilapia. According to Courtright, the company is still working on getting the technology right before going “large scale.” If trials are successful, the company will begin next year building its proprietary insect breeding and feeding facilities directly on-site for customers. The Yellow Springs headquarters, which currently has eight employees (including three full-time employees), would then mainly be used for research, development, training and engineering, Courtright said.

Producing and selling the fertilizer locally is important both to capture a waste stream and to support the Yellow Springs community, Courtright emphasized.

“We’re trying to be a good corporate citizen in this town,” he said. “How can you claim to be socially responsible when you’re not supporting the local market?”